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Subject[065/143] GFS2: Clean up gfs2_adjust_quota() and do_glock()
2.6.32-longterm review patch.  If anyone has any objections, please let us know.

------------------
From: Steven Whitehouse <swhiteho@redhat.com>

commit 1e72c0f7c40e665d2ed40014750fdd2fa9968bcf upstream.

Both of these functions contained confusing and in one case
duplicate code. This patch adds a new check in do_glock()
so that we report -ENOENT if we are asked to sync a quota
entry which doesn't exist. Due to the previous patch this is
now reported correctly to userspace.

Also there are a few new comments, and I hope that the code
is easier to understand now.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/gfs2/quota.c | 82 +++++++++++++++++---------------------------------------
1 file changed, 26 insertions(+), 56 deletions(-)
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -15,7 +15,7 @@
* fuzziness in the current usage value of IDs that are being used on different
* nodes in the cluster simultaneously. So, it is possible for a user on
* multiple nodes to overrun their quota, but that overrun is controlable.
- * Since quota tags are part of transactions, there is no need to a quota check
+ * Since quota tags are part of transactions, there is no need for a quota check
* program to be run on node crashes or anything like that.
*
* There are couple of knobs that let the administrator manage the quota
@@ -65,13 +65,6 @@
#define QUOTA_USER 1
#define QUOTA_GROUP 0

-struct gfs2_quota_host {
- u64 qu_limit;
- u64 qu_warn;
- s64 qu_value;
- u32 qu_ll_next;
-};
-
struct gfs2_quota_change_host {
u64 qc_change;
u32 qc_flags; /* GFS2_QCF_... */
@@ -617,33 +610,19 @@ static void do_qc(struct gfs2_quota_data
mutex_unlock(&sdp->sd_quota_mutex);
}

-static void gfs2_quota_in(struct gfs2_quota_host *qu, const void *buf)
-{
- const struct gfs2_quota *str = buf;
-
- qu->qu_limit = be64_to_cpu(str->qu_limit);
- qu->qu_warn = be64_to_cpu(str->qu_warn);
- qu->qu_value = be64_to_cpu(str->qu_value);
- qu->qu_ll_next = be32_to_cpu(str->qu_ll_next);
-}
-
-static void gfs2_quota_out(const struct gfs2_quota_host *qu, void *buf)
-{
- struct gfs2_quota *str = buf;
-
- str->qu_limit = cpu_to_be64(qu->qu_limit);
- str->qu_warn = cpu_to_be64(qu->qu_warn);
- str->qu_value = cpu_to_be64(qu->qu_value);
- str->qu_ll_next = cpu_to_be32(qu->qu_ll_next);
- memset(&str->qu_reserved, 0, sizeof(str->qu_reserved));
-}
-
/**
- * gfs2_adjust_quota
+ * gfs2_adjust_quota - adjust record of current block usage
+ * @ip: The quota inode
+ * @loc: Offset of the entry in the quota file
+ * @change: The amount of change to record
+ * @qd: The quota data
*
* This function was mostly borrowed from gfs2_block_truncate_page which was
* in turn mostly borrowed from ext3
+ *
+ * Returns: 0 or -ve on error
*/
+
static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
s64 change, struct gfs2_quota_data *qd)
{
@@ -655,8 +634,7 @@ static int gfs2_adjust_quota(struct gfs2
struct buffer_head *bh;
struct page *page;
void *kaddr;
- char *ptr;
- struct gfs2_quota_host qp;
+ struct gfs2_quota *qp;
s64 value;
int err = -EIO;

@@ -700,18 +678,13 @@ static int gfs2_adjust_quota(struct gfs2
gfs2_trans_add_bh(ip->i_gl, bh, 0);

kaddr = kmap_atomic(page, KM_USER0);
- ptr = kaddr + offset;
- gfs2_quota_in(&qp, ptr);
- qp.qu_value += change;
- value = qp.qu_value;
- gfs2_quota_out(&qp, ptr);
+ qp = kaddr + offset;
+ value = (s64)be64_to_cpu(qp->qu_value) + change;
+ qp->qu_value = cpu_to_be64(value);
+ qd->qd_qb.qb_value = qp->qu_value;
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
err = 0;
- qd->qd_qb.qb_magic = cpu_to_be32(GFS2_MAGIC);
- qd->qd_qb.qb_value = cpu_to_be64(value);
- ((struct gfs2_quota_lvb*)(qd->qd_gl->gl_lvb))->qb_magic = cpu_to_be32(GFS2_MAGIC);
- ((struct gfs2_quota_lvb*)(qd->qd_gl->gl_lvb))->qb_value = cpu_to_be64(value);
unlock:
unlock_page(page);
page_cache_release(page);
@@ -740,8 +713,7 @@ static int do_sync(unsigned int num_qd,

sort(qda, num_qd, sizeof(struct gfs2_quota_data *), sort_qd, NULL);
for (qx = 0; qx < num_qd; qx++) {
- error = gfs2_glock_nq_init(qda[qx]->qd_gl,
- LM_ST_EXCLUSIVE,
+ error = gfs2_glock_nq_init(qda[qx]->qd_gl, LM_ST_EXCLUSIVE,
GL_NOCACHE, &ghs[qx]);
if (error)
goto out;
@@ -796,8 +768,7 @@ static int do_sync(unsigned int num_qd,
qd = qda[x];
offset = qd2offset(qd);
error = gfs2_adjust_quota(ip, offset, qd->qd_change_sync,
- (struct gfs2_quota_data *)
- qd);
+ (struct gfs2_quota_data *)qd);
if (error)
goto out_end_trans;

@@ -828,8 +799,7 @@ static int do_glock(struct gfs2_quota_da
struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
struct gfs2_inode *ip = GFS2_I(sdp->sd_quota_inode);
struct gfs2_holder i_gh;
- struct gfs2_quota_host q;
- char buf[sizeof(struct gfs2_quota)];
+ struct gfs2_quota q;
int error;
struct gfs2_quota_lvb *qlvb;

@@ -853,22 +823,23 @@ restart:
if (error)
goto fail;

- memset(buf, 0, sizeof(struct gfs2_quota));
+ memset(&q, 0, sizeof(struct gfs2_quota));
pos = qd2offset(qd);
- error = gfs2_internal_read(ip, NULL, buf, &pos,
- sizeof(struct gfs2_quota));
+ error = gfs2_internal_read(ip, NULL, (char *)&q, &pos, sizeof(q));
if (error < 0)
goto fail_gunlock;
-
+ if ((error < sizeof(q)) && force_refresh) {
+ error = -ENOENT;
+ goto fail_gunlock;
+ }
gfs2_glock_dq_uninit(&i_gh);

- gfs2_quota_in(&q, buf);
qlvb = (struct gfs2_quota_lvb *)qd->qd_gl->gl_lvb;
qlvb->qb_magic = cpu_to_be32(GFS2_MAGIC);
qlvb->__pad = 0;
- qlvb->qb_limit = cpu_to_be64(q.qu_limit);
- qlvb->qb_warn = cpu_to_be64(q.qu_warn);
- qlvb->qb_value = cpu_to_be64(q.qu_value);
+ qlvb->qb_limit = q.qu_limit;
+ qlvb->qb_warn = q.qu_warn;
+ qlvb->qb_value = q.qu_value;
qd->qd_qb = *qlvb;

if (gfs2_glock_is_blocking(qd->qd_gl)) {
@@ -1127,7 +1098,6 @@ int gfs2_quota_refresh(struct gfs2_sbd *
gfs2_glock_dq_uninit(&q_gh);

qd_put(qd);
-
return error;
}




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